| Popis: |
Lewis acids TaF5 and NbF5 are reported to catalyze the conversion of chloroethanes or chloroethylenes in the presence of HF to make HCFC-123, an HCFC alternative to CFC-11 (CFCl3) [A.E. Feiring, US Pat. 4 258 225 (1981); W.H. Gumprecht, W.G. Schindel and V. Felix, US Pat. 4 967 024 (1990)]. However, both TaF5 and NbF5 are expensive for use on a commercial scale. The synthesis of anhydrous TaF5 and NbF5 from their corresponding metal oxides in a single step in situ and their use as catalysts to make HCFC-123 will be discussed. |
